1. Field of the Invention
The invention relates to a single-shell spring control arm, formed from sheet steel, for a wheel suspension of a motor vehicle, comprising a first end portion for attaching to a chassis beam, preferably a rear axle beam, a second end portion for attaching on the wheel side, and an increased-width portion which is arranged between the two end portions, and which comprises a spine having flanks projecting therefrom and which defines a spring seat for supporting a spring.
Spring control arms are used to guide a chassis wheel on a wheel suspension of a motor vehicle. They comprise a portion for supporting a spring or a spring/shock absorber arrangement, which in turn is supported against the vehicle bodywork.
Spring control arms are often subject to high alternating loads during driving. If the spring control arm is not sufficiently rigid, a widening or deformation of the spring control arm can occur in particular in the region of the spring support. In order to achieve a high load-bearing capacity in the region of the spring support, current known spring control arms are provided with one or more reinforcing auxiliary plates. For example cup-shaped shells are inserted into the increased-width portion of the spring control arm in the region of the spring support as reinforcing auxiliary plates. Furthermore, multi-shell spring control arms are known, which comprise, in the region of the spring pad, a closure plate which encloses the spring and is welded to the two flanks of a channel-shaped spring control arm shell.
2. Description of Related Art
DE 10 2004 008 957 A1 discloses a spring control arm for a wheel suspension that is formed from a spring control arm shell having a substantially U-shaped profile, the U-shaped profile comprising on its open side two crescent-shaped bridge plates which are arranged on both sides of the spring pad surface and are fastened to the spring control arm shell by rivets, screws or welded connections.
The production and incorporation of the additional shells or closure plates and bridging plates necessitates appropriate production steps, and this has an unfavourable effect on production costs. In addition, known multi-shell spring control arms sometimes have a relatively high component weight as a result of their reinforcing auxiliary plates.
DE 10 2006 032 595 A1 discloses a single-shell spring control arm, the integrally formed spring control arm shell of which comprises a first end portion for attaching on the vehicle-body side, a second end portion for attaching on the wheel side and an increased-width portion for supporting a spring. The portion having the increased width has a U-shaped profile, the free ends of which are each bent outwards to form a collar (flange). The portion having the increased width further comprises an annular surface, which has been folded outwards, as the spring seat. To improve the centring of the spring, an inwards facing protuberance is formed inside the annular surface and is provided with a central opening. This known single-shell spring control arm has a lower component weight than the known multi-shell spring control arms. Manufacturing steps, which are required with multi-shell spring control arms for the production and incorporation of the additional closure and bridging plates, are omitted during the production of the single-shell spring control arms.